DE112010004196T5 - Weight balanced engine piston - Google Patents

Abstract

A piston for an internal combustion engine has a piston crown with an outer cylindrical wall which is connected to and lies above a body part of the piston. The piston has at least one piston ring seal groove which is formed in the outer cylindrical wall and extends circumferentially around the piston head and a first oil collecting groove which is formed in the outer cylindrical wall under the at least one piston ring seal groove and is parallel to the at least one piston ring seal groove extends around an entire circumference of the piston. The first oil collection groove has a first width measured along a center line of the piston. A second oil collection groove is formed in the outer cylindrical wall under the first oil collection groove, extends parallel to the first oil collection groove around the entire circumference of the piston and has a width that is at least twice the width of the first oil collection groove.

Description

Technical area

This patent publication relates generally to internal combustion engines, and more particularly to pistons operating in engine bores.

background

Internal combustion engines include one or more pistons, which are connected by connecting rods to a crankshaft, and are typically arranged to reciprocate within bores, which are known to be formed in a crankcase. A typical piston has a head portion that at least partially defines a combustion chamber in each bore and a piston skirt typically having a bolt aperture and other support structures for connection to the connecting rod of the engine. In general, a piston is shaped to generally have a cup shape, with the piston head forming the base and the piston skirt portion connected to the base and surrounding an enclosed gallery of the piston. In typical applications, lubricating oil is supplied by the engine within the gallery of the piston during operation to convectively cool and lubricate various parts of the piston.

A typical piston head also has a cylindrical outer wall with one or more circumferential continuous grooves formed therein. These grooves typically extend parallel to one another and are sized to receive sealing rings therein. These seal rings create sliding seals between each piston and the crankcase bore in which it operates. Typically, the groove closest to the skirt of the piston receives a scraper ring arranged to scrape off oil adhering to the walls of the piston bore during a downstroke of the piston. Oil remaining and wetting the walls of the bore following the downstroke of the piston may continue to enter the combustion chamber and burn during operation of the engine.

A known solution for improving the removal of oil that can be found on the bore walls during a downstroke of the piston is in the U.S. Patent 6,557,514 which is hereby incorporated by reference in its entirety (hereinafter referred to as "the '514 patent"). The '514 patent discloses a piston having an outer wall defined in part by an annular belt and having an oil gallery defined internally in the piston. An oil drain groove is machined into the outer surface of the annular belt of the cylindrical side wall of the piston head, under two piston ring sealing grooves. The oil drain groove is defined in part by a bottom wall that extends circumferentially around the piston but is interrupted so that oil that has entered the oil groove can drain down into the crankcase of the engine. An upper wall of the oil drain groove extends around the circumference of the body of the piston. As disclosed in the '514 patent, the upper annular grooves receive piston rings while the lowermost groove is free of piston rings and arranged to collect the oil as the piston makes a downward stroke.

The oil collecting groove, which in the '514 Patent is at least partially effective in reducing the amount of oil remaining on the cylinder wall after the piston has made a downward stroke.

With the foregoing background, it is sometimes the case that a mature engine design, particularly a design that is already sold to customers, needs improvements in the performance of the cost or the source of components, which will make the engine more successful in the marketplace. Such engine product improvements are particularly valuable to an engine manufacturer when maintaining backward compatibility of new components to be used in place of original engine components. Nevertheless, it has traditionally been the case that engine pistons are not considered as components that can be redesigned in the middle of a product life cycle of a particular engine.

The fact that engine pistons are not suitable as components that can be redesigned to fit an existing engine and replace an existing basic piston design relies in large part on constructive changes made to a piston often will require a concomitant series of changes to other engine components. For example, an updated piston design may cause changes in the weight balance, performance, and / or other functional attributes of the piston, which in turn necessitates changes to the crankshaft counterweights or changes to the connecting rods and engine calibration. In addition, it is contemplated that service providers offering engine overhaul could replace some pistons, but leave others with less wear or damage in the engine, which would cause significant performance problems if the replacement piston had a different weight compared to the original piston. Any such changes to the Engine component design makes the retrofitting of certain components, such as pistons, effectively inappropriate for engines currently in production.

Brief description of the drawings

1 is a sectional view of a known Monotherm ^® piston which is made of meal, which is hereinafter referred to as basic flask.

2 is a sectional view of a known Mono ^® piston Steel, which is manufactured by Federal Mogul, which is hereinafter referred to as piston blank.

3 is a view of a first embodiment of a piston according to the disclosure.

4 - 7 are different views of the im 1 shown piston.

8th is a view of a second embodiment of a piston according to the disclosure.

9 - 12 are different views of the in 6 shown piston.

Detailed description

This disclosure relates to pistons for use in internal combustion engines, and more particularly in direct injection compression-ignition engines. In particular, the disclosure provides a method of achieving a design of pistons that are backward compatible with engines having basic pistons that are already in service. As used herein, the term backward compatibility refers to the ability to interchangeably use original pistons or basic pistons and retrofitted pistons using machined piston blanks without requiring changes to other engine components. Thus, such retrofitted or newly designed pistons may be used during the design of new engines, or even replace basic pistons during servicing. In addition, retrofitted pistons can be positioned as aftermarket parts to improve the performance of existing engines.

Two examples of pistons 10 and 20 The prior art are each in the 1 and 2 shown. The piston 18 who in 1 is illustrated, is a Monotherm ^® piston and may be referred to as the basic piston. The in 2 illustrated pistons 20 is a Monosteel ^® piston and can be referred to below as a piston blank. For simplicity, features of the basic piston 18 and the piston blank 20 that have the same or similar characteristics of the improved pistons 100 and 200 are, which are disclosed below, denoted by the same reference numerals in the different views of the figures.

The in 1 shown basic piston 18 has several features unique to its construction. In particular, the basic piston 18 made by a forging process of a uniform metal mass. The basic piston 18 has a tapered part 12 on, the one headboard 104 of it, of a body part 106 separates. An included oil cooling gallery 102 is inside the header 104 shaped and is made of an annular edge 14 enclosed. For the purposes of the present disclosure, the basic piston will be described 18 considered as a fundamental component suitable for a particular engine application and already installed in engines sold to customers and working in service. For various reasons, such as component cost, availability, retrofit or replacement parts, or desirable engine performance enhancements, an engine manufacturer may want the basic piston 18 to replace with an improved piston, but without the need to continue to replace other engine components associated with the piston, such as the crankshaft.

With regard to replacement of service or overhaul of components, certain components, such as pistons, may be scheduled to be replaced at certain service intervals, or at least inspected and replaced if the wear is excessively large. Pistons and piston rings are usually replaced during overhaul, but other parts, such as the crankshaft and the camshaft, are usually not replaced, if possible. If a piston is to be replaced during such a service event, certain aspects of the basic piston should be preserved, and certain aspects of the replacement piston should not be significantly different than the basic piston, to ensure proper performance and emission control. The replacement piston should be "weight balanced" or should generally be the same weight as the basic piston. The replacement piston should have a substantially similar piston cavity as the basic piston, and the annular groove geometry and annular groove arrangement should be similar to ensure proper performance and emissions control.

A piston blank 20 is in 2 shown. The piston blank 20 may be a piston that is already available from a piston manufacturer that has many desirable features that are already included in its construction but that lack certain aspects, such as weight. Characteristics of the piston blank 20 that are the same or similar, as the characteristics of the basic piston 18 or the characteristics of the improved pistons 100 and 200 like those in the 3 - 12 are denoted by the same reference numerals for simplicity. In one embodiment, the piston blank 20 be heavier in small dimensions than the basic piston 18 For example, less than 1 gram or larger amounts, for example, 105 grams or more.

Two embodiments of improved pistons suitable for retrofitting are disclosed herein. Each of the improved pistons illustrates a weight balance process performed on a piston blank to match the weight of a basic piston. For example, from the piston 200 (as in 8th - 12 shown) more weight removed than from the piston 100 (as in 3 - 7 shown). The weight reduction of the improved pistons 100 and 200 is concentrated in weight reduction regions comprising the secondary oil collection channels, as discussed further below. Also disclosed is a method for optimizing the design of a piston for a particular engine application. Both disclosed embodiments are the result of a modification of a basic piston design or a piston blank. In the following description structural features of the basic piston will be described 18 ( 1 ), the piston blank 20 ( 2 ), the first embodiment of an improved piston 100 ( 3 - 7 ) and the second embodiment for an improved piston 200 ( 8th - 12 ), which are the same or similar, are designated for simplicity using the same reference numerals in the figures and described in the drawings. Nevertheless, it should be noted that pistons having features or structures other than those shown and described herein may be used.

In the 1 and 2 each illustrate the basic piston 18 and the piston blank 20 , 3 - 7 illustrate a first embodiment of a piston 100 , 6 - 10 illustrate a second embodiment of a piston 200 , The pistons 100 and 200 As they are shown, are mono Steel ^® pistons with an enclosed cooling gallery 102 between a head or piston head part 104 and a bolt or body part 106 is defined. The pistons 100 and 200 as they are illustrated, were from the piston blank 20 manufactured so that each matches the weight of a corresponding basic piston, such as the basic piston 18 ( 1 and each has substantially similar annular grooves and a similar piston bowl geometry to the corresponding basic parts.

In each piston forms the body part 106 two bolt holes 107 , The head or piston bottom and body parts 104 and 106 The piston 100 and 200 can huddle together 108 be connected by friction welding. Every piston 100 or 200 defines an outer cylindrical wall 110 that stretch over the head and body parts 104 and 106 extends, as best in the detail section of 7 or 12 is shown. The headboard 104 defines a combustion or piston recess 114 , which is a depression, in the head or piston head part 104 is formed, which extends over a generally central part thereof. The piston recess 114 is from an upper end face 116 surrounded in the illustrated embodiment, perpendicular to the outer cylindrical wall 110 cuts. The piston recess 114 cuts the upper face 116 along an edge 117 , As is known, the shape of the piston recess 114 be optimized to provide desired combustion characteristics during operation of an engine.

A plurality of annular grooves extending parallel to each other over a peripheral portion of the outer cylindrical wall 110 extend, has an upper piston ring groove 118 on, the closest to the top 116 is arranged, a lower piston ring groove 120 which, as shown, under the upper piston ring groove 118 is arranged, and a first Ölsammelnut 122 on that under the lower piston ring groove 120 is arranged. The upper and lower piston ring grooves 118 and 120 as well as the first oil collection groove 122 segment the outer cylindrical wall 110 in a variety of "webs" or, in other words, tapes of the cylindrical wall surface containing the grooves 118 . 120 and 122 separate and object to each other. In particular, a first or upper bridge 124 between the upper piston ring groove 118 and the transition to the upper end face 116 defined, a second bridge 126 is between the upper and lower piston ring grooves 118 and 120 defined and a third bridge 128 is between the lower piston ring and the first oil collection grooves 120 and 122 although other configurations or numbers of piston ring and oil collection grooves may be used.

As can be seen from the figures, the first, second and third bars are 124 . 126 and 128 generally with the outer cylindrical wall 110 aligned. In other words, points on the first, second and third jetties 124 . 126 and 128 are all about the same radial distance from a centerline 130 of the piston 100 or 200 regardless of any drawing angles or other variations of the cylindrical shape of the outer cylindrical wall 110 that may be present on the piston.

When a piston is installed in an engine, every piston is 100 or 200 disposed within a cylinder bore (not shown) and has a combustion ring seal (not shown) disposed within the first or upper piston ring groove 118 in sealing contact between the piston 100 or 200 and the cylinder bore is arranged. The combustion ring seal operates to fluidly separate combustion byproducts and combustible mixtures that are present within the cylinder above the piston. A scraper ring (not shown) may be located within the lowermost or second piston ring groove 120 be arranged. The wiper ring may operate to strip oil adhered to the walls of the cylinder during a downstroke of the piston, as previously discussed. Oil collected by the scraper ring may at least temporarily in the first oil collection groove 122 be collected before it runs back down the piston into the crankcase of the engine (not shown). In the illustrated embodiments, one or more drain ports connect 132 Fluidly the first Ölsammelnut 122 with the enclosed cooling gallery 102 , which allows the oil which is in the groove 122 is collected, runs through the piston into the crankcase of the engine.

The description has until now features of the pistons 100 and 200 discussed, usually on the basic piston 18 ( 1 ) and on the piston blank 20 ( 2 ), which are used in the illustrated embodiments, and which define basic performance characteristics of the engine as discussed below. Every piston 100 or 200 However, has features that the Kolbenrohteil 20 have been added to optimize the weight of the piston blank and to improve the ability of the piston to efficiently remove oil that has collected during the downstroke of the piston in specific engine applications. In one embodiment, a piston blank may be modified by machining the piston blank such that weight is removed therefrom so that the weight of a basic piston design is achieved by the improved pistons disclosed herein. In such cases, material removed from the piston blank may achieve sufficient weight reduction that matches the weight of the basic piston while also allowing the formation of the secondary oil collection grooves and other improved features described herein. In general, it should be noted that reducing the weight of a reciprocating piston in the engine improves the moment of inertia of the engine and thus increases the useful power output of the engine. In addition, the ability of a piston to more easily remove accumulated oil from a cylinder wall during the downstroke of the piston can result in reduced engine oil consumption and reduced emissions. The unique features of each of the two embodiments shown will now be discussed in more detail. The piston 100 has an additional or second oil collection groove 300 on, the best in 7 is shown. Unlike the first oil collection groove 122 is the second oil collecting groove 300 much wider and defines a first channel 302 and a second channel 304 and a bridge part 306 , with reduced diameter, between the first and second channels 302 and 304 is arranged. In the illustrated embodiment, the first channel extends 302 revolving around the piston 100 just above a ring-shaped projection 308 , the bridge part 306 defined with reduced diameter. The second channel 304 is partially around the entire circumference of the piston 100 shaped around, however, is over parts of the body part 106 interrupted with reduced diameter, the bolt holes 107 record as best in 5 shown. A chamfer 310 is along the interface between the bottom of the second channel 304 and the body part 106 of the piston 100 shaped.

In the specific embodiment of the piston 100 in the 3 - 7 illustrated has the second oil collecting groove 300 a total width of about 9.5 mm. Each of the first and second channels 302 and 304 can be with a width of about 2.5 mm, which is along the length of the piston 100 is defined and shaped to a depth of about 5.34 mm. The jetty 306 with reduced diameter ( 7 ) is between the first and second channels 302 and 304 has a width of about 4.5 mm and is radially about 1.34 mm from the surface of the outer cylindrical wall 110 arranged; in other words, the jetty 306 with reduced diameter has a height in the radial direction, relative to the piston 100 of about 4 mm. The chamfer 310 ( 7 ) extends approximately 1.5 mm below the lower edge of the second channel 304 at an angle of about 20 degrees.

Furthermore, the upper edge or the edge closest to the combustion recess or piston bowl 114 of the piston 100 about 33 mm below the upper front 116 located.

Similar to the piston 100 , points in the 8th - 12 shown piston 200 an additional or second oil collecting groove 400 on, the best in 12 is shown. Unlike the first oil collection groove 122 is the second oil collecting groove 400 much wider than any of the other grooves in the piston 200 is shaped. In the illustrated embodiment, the second oil collection groove extends 400 revolving around the piston 200 but is about parts with reduced diameter of the piston part 106 interrupted, which the bolt holes 107 record as best in 10 shown. A chamfer 310 is along the interface between the lower part of the second oil collecting groove 400 and the body part 106 of the piston 200 formed.

In the specific embodiment of the piston 200 which in the 8th - 12 is illustrated, the second Ölsammelnut 400 with a width of about 9 mm, which is along the length of the piston 200 is defined and shaped to a depth of about 5.34 mm. The chamfer 310 ( 12 ) extends about 1.5 mm below the lower edge of the second oil collection groove 400 at an angle of about 20 degrees. In addition, the upper edge or edge is closest to the combustion bowl or piston bowl 114 of the piston 100 about 32.5 mm below the upper end 116 located.

Industrial applicability

The performance of the disclosed embodiments for the pistons 100 and 200 in the engine was rated and with the performance of the basic piston 18 previously used in the same engines. The results of this comparison showed an unexpected improvement in the operation of the engines compared to certain engine operating parameters that can affect the efficiency of the engines' operation, as well as certain parameters that affect the reliability and longevity of the engines. In sum, it is assumed that the additional oil collecting grooves, for example, the second oil collecting groove 300 of the piston 100 (see, for example 7 ) and the second oil collection groove 400 (see, for example 12 ) have had a positive and unexpected effect in reducing the peak operating temperature of certain areas of the piston, as well as meaningfully and significantly reducing the oil consumption of the engines in which they operate. In addition, there has been a significant reduction of oil deposits in the first land and within the first piston ring groove of the pistons 100 and 200 compared to the oil deposits observed on the basic pistons operating under the same test cycles. A brief presentation of these performance improvements follows.

The first area of unexpected improvements in the operation of the pistons 100 and 200 refers to peak temperatures along the edge 117 the combustion recess or piston recess 114 (see, for example 5 and 10 ), which is also the peak temperature of the piston during operation. In the basic design, the steady state temperature at the edge of the piston bowl was about 504 degrees Celsius for an engine operating at 1800 revolutions per minute (RPM) and rated at about 900 horsepower for the engine under test. ° C). In the same engine application, with the engine operating at the same engine speed and under the same performance conditions, the piston yielded 100 a temperature in the steady state at the edge 117 the piston recess 114 from about 427 ° C. This reduction in the temperature of the piston in this region represents an improvement of about 15.3%, which was not expected before the test. Other areas of improved pistons 100 and 200 showed similar improvements in operating temperature over corresponding areas of the basic pistons operating in the same engines under the same conditions.

Another area of unexpected improvement in the operation of an engine in which the pistons 100 or 200 were installed and worked refers to the engine "used" oil. As is known, the oil consumption during operation of the engine may be attributed to various factors, including that oil evaporates within the engine crankcase, which is removed via a crankcase ventilation system, the oil passes through the seals of the piston and enters the combustion cylinders, and others factors. It has been determined that the improved pistons 100 or 200 reduced engine oil consumption by 50% or more compared to a basic piston. For example, an engine operating at a nominal state for about 250 hours may consume oil at a rate of about 0.0005 pounds of oil (about 0.002 kilos of oil) per horsepower in operation with the basic pistons. A test using the same engine operating under the same conditions for the same time period, but either the improved piston 100 or the improved piston 200 reached an oil consumption rate that was about 0.00024 lbs (about 0.0009 kg) of oil per hp-hr, which represents a reduction of about 52% of the engine oil consumption rate over the basic piston design.

An additional example of improved engine operation using the pistons 100 or 200 was observed. Consequences of disassembly of test engines containing the basic pistons as well as of engines incorporating the improved pistons 100 or 200 A significant reduction in the amount of oil deposits found in the first or upper piston ring groove was observed 118 and on the second jetty 126 (please refer 7 and 12 ) The piston 100 and 200 had accumulated compared to the basic pistons. This result was also unexpected.

Based on the foregoing, it can be said that the width of the second oil collecting groove 300 or 400 as in each case in the 7 and 12 shown, is substantially larger than the width of the other grooves of the piston.

For example, the first oil collection groove 122 ( 7 and 12 ) has a width of about 4 mm, which is typical for engine pistons. In addition, the piston ring sealing grooves 118 and 120 of similar width. This means that the second oil collecting groove 300 or 400 on each piston 100 or 200 more than twice as wide as a typical groove, which is then found in the engine piston, such as pistons with a nominal bore or outer bore diameter of about 136 mm. As a practical matter, this difference in width between the second oil collecting grooves and the other grooves provided in a piston as disclosed herein avoids certain assembly errors, such as installation of a piston ring within an oil collecting groove and others, especially in the case automated assembly methods are used. For example, a robotic device for installing a piston ring may be constructed and arranged to discriminate against the second, wider oil collection groove when determining which grooves certain ring seals should be installed in.

It will be understood that the foregoing description provides examples of the disclosed system under the art. It is contemplated, however, that other embodiments of the disclosure may differ in detail from the foregoing examples. Any reference to the disclosure or examples thereof is intended to be in reference to the specific example just discussed at this point and is not intended to imply any limitation on the scope of the disclosure in general. Any reference to a distinction and a less preferred embodiment regarding certain features is intended to indicate that these features are less preferred, but this is not intended to fully exclude such features from the scope of the disclosure except as otherwise indicated.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6557514 [0004, 0005]

Claims (10)

Piston ( 100 ) for an internal combustion engine, comprising: a piston head of the piston ( 100 ), with a body part ( 106 ) of the piston ( 100 ), and above it, wherein the body part ( 106 ) two bolt holes ( 107 ), and wherein the piston crown of the piston ( 100 ) an outer cylindrical wall ( 110 ) Are defined; at least one annular sealing groove of the piston ( 100 ), which in the outer cylindrical wall ( 110 ) is formed and circumferentially around the piston head of the piston ( 100 ) extends; a first oil collecting groove ( 122 ), which in the outer cylindrical wall ( 110 ) under the at least one annular sealing groove of the piston ( 100 ) is formed and parallel to the at least one annular sealing groove of the piston ( 100 ) around the entire circumference of the piston ( 100 ), wherein the first oil collection groove ( 122 ) a first width, measured at a center line ( 130 ) of the piston ( 100 ) Has; and a second oil collecting groove ( 300 . 400 ), which in the outer cylindrical wall ( 110 ) under the first oil collecting groove ( 122 ) is formed parallel to the first Ölsammelnut ( 122 ) around the entire circumference of the piston ( 100 ) and has a width which is at least twice as large as the width of the first oil collection groove ( 122 ). Piston ( 100 ) according to claim 1, wherein the outer cylindrical wall ( 110 ) has a first diameter, and wherein a web ( 306 ) of reduced diameter through an annular part of the piston ( 100 ) defined within the second oil collection groove ( 300 . 400 ), wherein the web ( 306 ) of reduced diameter, has a diameter which is less than the diameter of the outer cylindrical wall ( 110 ). Piston ( 100 ) according to claim 2, wherein the annular part is the second oil collecting groove ( 200 . 400 ) into a first channel ( 302 ) disposed over the annular member and dividing a second channel disposed below the annular member. Piston ( 100 ) for an internal combustion engine, comprising: a first end defining at least one annular groove, the at least one annular groove being sized to define a ring for the piston ( 100 ) in it; a second end containing a body part ( 106 ) Are defined; and a weight balancing section disposed between the first and second ends of the piston ( 100 ), wherein the weight compensation portion of the piston ( 100 ) having recessed portions sized to prevent the ring for the piston ( 100 ) enters the recessed parts. Piston ( 100 ) according to claim 4, wherein an outer diameter of the piston ( 100 ) is about 136 mm, and wherein the recessed portions of the counterweight portion are an annular groove defined by a depth of about 5.34 mm and a width of about 9 mm. Piston ( 100 ) for an internal combustion engine, comprising: a first end defining at least one annular groove that is structured and arranged to form a ring for the piston ( 100 ) in it; a second end defining a piston skirt; a weight balancing section disposed between the at least one annular groove and the second end of the piston ( 100 ), wherein the counterweight portion defines recessed portions; and a barrier wall disposed between the at least one groove and the recessed portions of the counterbalancing section; wherein the barrier wall is structured and arranged to hold the ring therein. Piston ( 100 ) according to claim 6, wherein the recessed parts of the counterbalancing section are an annular groove defined by a depth of about 5.34 mm, the at least one groove being defined by a width of about 4 mm, and the barrier wall by a width is defined by about 4 mm. Method for producing a piston ( 100 ) for an internal combustion engine, wherein the piston ( 100 ) has a first end defining at least one annular groove, a second end defining a piston skirt, and an intermediate portion therebetween having generally the same diameter as that first end of the piston ( 100 wherein the improvement comprises: forming an oil collecting groove having a width at least twice as large as a width of an annular groove of the piston ( 100 ) in the piston ( 100 ), wherein the oil collecting groove is sized and fixed to the piston ( 100 ) is arranged as generally described in the present disclosure. Method for replacing a basic piston ( 18 ) in an engine by an improved piston ( 200 ), comprising: selecting a piston blank ( 20 ) having a first end defining a piston crown at one end thereof and an annular groove land, having a second end defining a piston skirt, and an intermediate portion therebetween generally of the same diameter as the first end of the piston (US Pat. 100 ), wherein the piston crown has a piston recess of substantially similar dimensions as a depression of the basic piston, the annular groove member having a plurality of annular grooves having substantially similar dimensions and arrangement as the annular grooves of the reference piston (US Pat. 100 ); and machining a recessed part in the middle part, wherein a weight of the weight-balanced piston ( 100 ) substantially similar to a weight of the basic piston ( 18 ). The method of claim 9, further comprising: evaluating the weight balanced piston construction ( 100 ) by simulation test in the engine and by computer simulation, by comparison of a performance attribute of an engine, with the improved piston ( 200 ), with a corresponding performance attribute of an engine that is connected to the basic piston ( 18 ) is working.

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